Zoster strikes back

5. May 2010

A stroke is not only the result of an unhealthy life style. There is increasing evidence that also inflammations like shingles promote strokes and vessel sclerosis - most of all if the zoster virus afflicts the eyes.

Taiwanese researchers reported recently in the US magazine Neurology about remarkably close connection between shingles and stroke. According to the physicians at the Taipei University eight percent of the 658 patients with shingles had a stroke one year after the diagnosis. Only two percent of the control group of 200 zoster-free persons had the same disease. Particularly strong was the connection between zoster ophthalmicus and stroke. The neurologists in the team of Dr. Jau-Der Ho reported that the apoplexia-rate was increased by factor four. According to Ho this result was independent of whether or not the patients were treated antiviral. Dr. Maria Nagel from Denver and Dr. Gustavo A. Ortiz, Miami emphasized though in their comment that additional studies would be necessary to be able to evaluate the influence of an antiviral therapy and also steroids on the stroke risk. To Professor Howard S. Kirshner at the Vanderbilt University in Nashville, the results of the Taiwanese physicians are yet another strong reason for a vaccination prophylaxis against chickenpox.

The Taiwanese research had published another study with similar results in October 2009. They analyzed the progress of the disease of 7760 patients treated against shingles between 1997 and 2001. The data of 23,280 adults without shingles served as comparison. A total of 439 patients had a stroke during one year. A stroke rate of 1.71 percent in the zoster-group compared to 1.31 percent in the control group, the analysis resulted in 31 percent increased risk for an ischemic stroke. The incidents of hemorrhagic strokes were increased by the factor 2.8. The zoster ophthalmicus seems to be particularly dangerous as the researcher reported back then.

More atherosclerosis by viral vessel damages

Possibly the virus might cause a mild vessel damage in some people which goes without a stroke but promotes an existing atherosclerosis – as Ho and his colleagues assume. But they suggest not to come to the conclusion that shingles cause a stroke. The results of this study only show an indication of a potential connection which should be followed up though.

More strokes if severe stress

The researchers also explain that – besides the varicella vasculopathy – the pain-related stress might be part of the increased risk for stroke. Among others, Swedish researchers have reported last year that stress promotes strokes. A retrospective data evaluation of patients suffering from severe stress has shown an increase risk by factor 3.5. The head of studies Dr. Katarina Jood at the University of Goteborg writes in the BMC Medicine magazine that this retrospective analysis has to be interpreted with great care. Thus prospective studies should follow.

Known in children: Strokes after chicken pox

The connection between the chicken pox virus and vessel diseases is a long known fact. The varicella virus is the only human pathogenic virus that multiplies in the brain arteries. The US children neurologist Dr. Catherine Amlie-Lefond from Wisconsin reported a few months ago in the magazine Current Neurology and Neuroscience Reports that also ischemic strokes after varicella infections are not unusual – but in children. By the way: The speculation voiced time and again that chicken pox vaccination could lead to strokes could not be proved.

Many infections = thick vessel plaques

The results of the Taiwanese scientists about the connection between stroke and shingles complement a plentitude of studies. According to these, atherosclerosis – whether in the heart or also in the brain vessels – is promoted by infections. January 2010 Professor Mitchell S. V. Elkind and his colleagues at the Columbia University in New York reported a close association between infections and stroke as well as plaque-instability in the carotid artery.

The SU researchers had examined sera of 861 patients without stroke regarding antibodies against chlamydia pneumonia, helicobacter pylori, cytomegaly virus and herpes virus 1 and 2. They found particularly frequently antibodies against H. pylori (54.5 percent) and most of all against herpes virus (86.9 percent). The team observed the test persons over a period of eight years. During this time 67 test persons suffered from a stroke. If the researchers took all other risk factors into consideration, it showed that each and every infection took a small part in the stroke risk. But in the frequency of several infections they observed a significant risk feature. A bit more than half of the patients had plaques in the carotid arteries. The result of an analysis showed that the thicker this plaques was the more prominent was the so-called “infection burden”. The researchers applied a special index for quantitative assessment of the infection burden.

Elkind and his colleagues wrote in the professional magazine Stroke that there is more and more evidence of infections being a stimulus for an atherothrombosis and – transmitted by an inflammation – participating in the genesis of vessel sclerosis. “Our results might have consequences for practical work”, says the neurologist. “For example a strict fight against the pathogens could lower the stroke risk after all”. Future studies are needed though to confirm whether antiviral drugs or antibiotics are effective. For example antibiotics against chlamydia causing pneunomia have shown little effect as prevention against heart diseases. Whether or not this applies for the stroke has yet to be proven.